Strong enhancement of critical current density in both low & high fields and flux pinning mechanism under hydrostatic pressure in optimally doped (Ba,K)Fe2As2 single crystals

摘要

Strong pinning depends on the pinning force strength and number density ofeffective defects. Using hydrostatic pressure method, we demonstrate thathydrostatic pressure up to 1.2 GPa can significantly enhance flux pinning or Jcby a factor of up to 5 especially in both low and high fields in optimallydoped Ba0.6K0.4Fe2As2 crystals. Our analysis on the flux pining mechanismindicate that both pinning centre number density (Np) and pinning force (Fp)are greatly increased by the pressure and contribute to strong pinning.